This is a major cleanup of the LWKT message port code. The messaging code
is getting closer to being directly useable by userland. With these changes
message/port operations are now far better abstracted then they were before.
* Stale fields have been removed from struct lwkt_msg.
* lwkt_abortmsg() has been revamped to make it easier to support.
* lwkt_waitmsg has been converted to a port function.
* mp_*port() function fields have been renamed for better readability.
* ms_cleanupmsg has been removed from struct lwkt_msg.
* Union sysmsg is now struct sysmsg.
* A copyout function has been added to struct sysmsg.
* The system calls have been regenerated.